Clutch and brake mechanism



1944. w. J. PEETS ETAL 1 CLUTCH AND BRAKE MEfJHANISM Original Filed .April 19, 1941 Wilbur J ests 9918/ (john R025 I Wikmam. I

. watw/ M f Patented Feb. 1, 1944 CLUTCH AND BRAKE -MECHANISM 4 Wilbur J. Peets, Elizabeth, and John Roll, Union, N. J., assignors to The Singer Manufacturing Company, Elizabeth, N. 5., a corporation of New Jersey Original application April 19, 1941; Serial No.

1942, Serial No. 443,692

3 Claims.

This invention relates to driving devicesand more particularly to a unitary motor, clutch and brake arrangement which is particularly adapted for drivingmanufacturing types of sewing machines where frequent operation of the clutch and brake.to start and stop the machines is necessary.

The primary object of the invention is to provide improved means for preventing the driven element of the clutch from engaging the driving element after the friction material interposed between the two elements becomes worn.

With the above and other objects in view, as will hereinafter appear, the invention comprises the devices, combinations and arrangements of parts hereinafter set forth and illustrated in the accompanying drawing of a preferred embodiment of the invention, from which the several features of the invention and the advantages attained thereby will be readily understood by those skilled in the art.

The drawing is a longitudinal sectional view taken through an electric transmitter having our improvements embodied therein.

In the embodiment of this invention selecte for illustration, the frame of the transmitter is of hollow cylindrical form and comprises a motor field section In having the usual field core ll carrying exciting windings l2. The field frame section In is closed at one end by anend bonnet l3, and the other end is closed by an endbonnet it formed with a laterally extending flange 15 which forms a covering for the flywheel and clutch mechanism. The end bonnets l3 and M are clamped to the fieldframe by means of bolts, one of which is indicated as IS in the drawing.

Carried by the end bonnets l3 and H are ball bearings I1 and la in which is journaled the hollow motor shaft I9. One end of the shaft extends into the clutch housing, and fixed to it at a point intermediate the bearings I1 and I8 is a rotor which may be of the ordinary squirrel cage type. Located within the clutch housing I5 is the driving element or flywheel 2| which is secured to rotate with the shaft 19 by a key 22. Also carried by the shaft is are the ball bearings 23 and 24, the inner race of these bearings being fixed to the shaft by the nuts 23' and 24, respectively, to prevent both lateral and rotary motion relative to the shaft. Slidably mounted on the periphery of the outer race of the ball bearings 23 and 24 is the cup-shaped hub 25 of the driven clutch disk or element 26. The driven element 26 has a flange-like portion which is formed with smooth opposed faces 21 and 28 and has re- Divided and this application May 20,

movably secured to it, by any suitable means, a

pulley 29. Also carried by the transmitted frame is a brake holding member 30 which is adjustable to and from the driven element by the screw 3|. It will be understood that the driven element 26 is moved or shifted, by the sewing machine operatorbetween the driving element and the brake by means of a rod 3! which is actuated by a sleeve 32 having a steep pitched thread 33. The sleeve 32 may be turned by a lever or any other suitable means. For a more detailed and complete description of the mechanism above described reference may be had to the copending applications of Peets and Roll, Serial No. 296,598, filed Sept. 26, 1939, now Patent No. 2,274,457, issued February 24, 1942, or Serial No. 389,286, filed Apr. 19, 1941; the present application being a division of application Serial No. 389,286.

Interposed between the driving element 21 and the driven element 26 is a friction ring comprising a ring of resilient sheet-metal 35 which has cemented to one of its faces a clutch facing or ring of friction material 36, preferably made of cork or the like. When the clutch is slipped so that the machine will operate slowly, or when the machine is stopped and started every few seconds, the flange of the driven element 26 and the friction ring 35 generate heat and become hot thereby causing rapid disintegration of the friction ring. To avoid this overheating, we have provided the driven element 28 with openings 39 which are arranged adjacent the hub, and the facing 36 of the friction ring has been formed with radially arranged slots 31. The rotation of the friction ring causes the slots 31 to act as a centrifugal fan and draw air through the opening 39 and between the driving and driven elements to cool these elements, the air being dis charged at the outer periphery of the friction ring. It will be understood that the friction ring for the brake is identical with that used for the driven element.

To avoid metal to metal contactbetween the driving element and the driven element after the clutch facing has become worn, we have formed the interior bore of the hub 25 with a shoulder 40 which is arranged so that it will engage the outer race of the ball bearing 23 before the driven element will engage the metal ring 35, or in other words the distance between the outer race of the ball bearing 23 and the shoulder 40 is slightly less than the distance between the face 21 of the driven element 28 and the metal ring 35 which is fixed to the flywheel 2|. With this construction it will be obvious that the possibility of scoring the contacting face 21 of the driven element 28 is eliminated.

It will also be obvious that as the outer race of the ball bearing 23 rotates with the driven element the contacting surface between theshoulder 40 and the outer race will not become scored due to contact therebetween.

Having thus set forth the nature of the invention what we claim herein is:

1. In a transmitter unit, in combination, a

, metallic driving element, means for actuating said element, a non-metallic clutch facing carried by said driving element, a metallic driven element arranged coaxially of the driving element and slidable towards and away from said driving element, a ball bearing having inner and outer races located between said elements with the inner race in engagement with the driving element, and stop' means on said driven element which. is adapted to engage the outer race of said ball bearing to prevent metal to metal contact between the driving and driven element when the nonmetallic clutch facing is worn thin.

2. In a transmitter unit, in combination, a motor having a shaft with a metal driving clutch element fixed thereto, a metal driven clutch element carried by said shaft, a clutch facing of nontween the driving and driven clutch elements when the clutch facing becomes worn.

3. A power-transmitter including, in combination, coaxially disposed rotary driving and driven elements relatively shiftable axially, a ballbearing having an inner race-ring secured against movement relative to said driving element, said ball-bearing having an outer race .ring slidably supporting th driven element, a

friction facing carried by one of said elements between proximate faces of said elements, and stopmeans adapted to engage the said outer race ring of the ball bearing for limiting approach to I each other of said proximate faces incidental to wear of said friction facing.

WILBUR. J. PEETS. JOHN ROLL. 

